also: ねつしせん
gaze of keen interest; close attention
Used when someone is watching something with intense curiosity, fascination, or scrutiny. Often implies a focused, almost burning interest.
They are watching the new product with keen interest.
His research is receiving close attention from the academic community.
Standard kanji spelling; the reading ねっしせん is the most common pronunciation.
Alternate reading; less common but still encountered.
Compound of 熱 (netsu, 'heat') + 視線 (shisen, 'gaze'). The reading ねっしせん results from a common sound change (促音便) where つ becomes a small っ before certain consonants.